Abstract
C5 fraction, which accounts for 15-25% in naphtha, consists of molecules such as isoprene (IP), pentadiene (PD), cyclopentene(CP), and cyclopentadiene (CPD) can be used to manufacture petroleum resin and other high value-added products. Yet it is often burned as fuel and not fully utilized because separation of these products with close boiling points is difficult. One common process is to react CPD itself to form dicyclopentadiene (DCPD) so that it can be separated from the other C5 molecules. Extractive distillation was also used to recover alkynes from light ends. Such a process involves use of multiple separation columns and reactors. Furthermore, it was found that the reactor is highly coupled with one of the separation columns by a recycle stream, leading to snowball effect and difficulty in control. Hence a wide range of opportunities for process intensification and integration was available. It was found that the entire separation process can be substantially simplified by reducing number of reaction zones from 2 to 1 and number of columns from 8 to 6. Such a simplification increases product concentration of DCPD from a range between 85. wt% and 92. wt% to 99. wt%, while maintains the high purity (>99.75wt%) for the IP stream and specified purity (> 89.90wt%) for the PD plus CP stream. This process can be further simplified by using thermal coupling and external heat integration. Such simplifications and intensified techniques lead to substantial reduction in capital costs, energy costs as well as process operability.